Fresh-faced no longer, now the Prime Minister is the one on trial

For the first time since he became leader of the Labour Party there is intense speculation about the future of Tony Blair. At the end of a torrid year there is a dramatic question in the air. Will Blair cease to be Prime Minister during 2004?

Those who raise the question range across the spectrum of his party. They are not just familiar internal opponents. Some Blairite allies who have worked closely with the Prime Minister worry about his health and the strategic ineptitude that has led to a crisis over top-up fees for universities. In private they speak apprehensively about the need for a dignified exit strategy in case a prime ministerial resignation becomes either desirable or unavoidable.

Some Labour MPs contemplate his departure more gleefully. Several have called publicly for his resignation, including the former cabinet minister Clare Short. Indeed, rarely a day passes when Short does not call on Blair to depart. In between these two groups are a growing number of critics who are becoming more vocal and impatient. They include allies of Gordon Brown who want the Chancellor to succeed Blair in the coming 12 months. Until recently these Brownites have been more restrained than Short (who also wants Brown to succeed), but they are starting to flex their muscles visibly.

Then there is the mighty Chancellor himself, who has profound doubts about the Blairite course in spite of a limited rapprochement at the end of this year. It goes without saying that his ambition to be Prime Minister is undimmed. Also making his presence felt is Robin Cook, no friend of Gordon Brown's but, on several policy fronts, proving to be a subtly forensic critic of the Prime Minister. The former foreign secretary's onslaughts are all the more devastating because they are mischievously spiced with flattery for some parts of Blair's record.

Tony Blair's critics have some good cause for their restiveness. During this year the leader pushed his party as far as it would go and then decided to push it quite a lot further. The original vote in the Commons on whether Britain should go to war against Iraq produced a massive backbench revolt. In a way that is still underestimated, many cabinet ministers were also privately uneasy. In a British context, this was Blair's war, almost his war alone. The way he chose to go about it was also a solo exercise - seeking UN backing for the conflict and expressing confidence that the support would be forthcoming. This was a calamitous failure for British foreign policy, made worse by the desperate scapegoating of France.

In terms of domestic politics, Labour MPs have become more rebellious with the passing of time. In the first term much overblown nonsense was written about the control freakery exerted by the likes of Alastair Campbell and Peter Mandelson. In reality, backbenchers controlled themselves, partly out of genuine enthusiasm over Labour being in power after 18 years of opposition, and also because of a youthful ambition. Most of them wanted to be ministers. Now the Labour benches are filled with former ministers and those who realise their moment has passed. These MPs are much harder to control.

This does not mean that Blair is doomed. Indeed, in my view he will still be Prime Minister in a year's time, above all for the simple reason that he wants to be Prime Minister in a year's time. It is almost impossible to dislodge a prime minister resolved to continue in power. Margaret Thatcher was an exception, but by November 1990, when her own party removed her, she had been Prime Minister for more than 11 years and the Conservatives were miles behind in the opinion polls. Blair has served for a mere six and a half years and his party is not in such a vulnerable position. More typical of prime ministerial staying power is Harold Wilson. From 1968 onwards there was endless speculation about his position. He went on to fight three more elections, winning two of them. He did so in far more precarious circumstances than Blair finds himself in at the end of 2003.

Admittedly, Wilson was helped by the failure of internal dissenters to unite around an alternative candidate. In that respect Blair is in a less secure position. He has a single credible contender for the throne, but Brown does not want his fingerprints anywhere near the political corpse of Blair. He knows that his only hope of succession is if the Prime Minister goes of his own volition. There will be no direct challenge from Gordon Brown in 2004. He waits to see what happens next.

What appears to be happening next is another prime ministerial relaunch. As I revealed here in September, Blair will reshuffle his cabinet once Lord Hutton has given his verdict next month. On the opposite page, the former cabinet minister Stephen Byers, who is in regular contact with Blair, suggests that there will also be an ideological relaunch. Byers is not clear about the nature of the fresh prime ministerial message, nor whether it will be especially fresh, but I cite these vague signs of forward thinking as an example of Tony Blair's determination to carry on.

My prediction is that he will press on but as a weakened leader. He has lost for good the fresh-faced authority that helped him to dominate British politics from the point at which he became leader of his party until the last election. His agenda in the coming months is hardly the basis for a new dawn. Next month's vote in the Commons on top-up fees will be a disaster whatever happens. If Blair wins, it will be as a result of concessions that render the policy virtually meaningless. If he loses, it will be another blow to his standing. As a double whammy, his parliamentary party would be portrayed in the media as "old Labour" and "anti-reform" in its refusal to back the policy. Either way, this will not be a good start to the year, and it is unclear what policies will provide the Government with fresh momentum from then on.

There is another issue arising out of the question that began this column. With senior figures in his own party wondering whether he will survive as Prime Minister for much longer, Blair has to prove that he is still worthy of the job. This is a hugely significant shift. Until recently the Labour Party had to live up to the unique popularity of Blair. Now he has to demonstrate that he deserves to be its leader. That is what has changed in 2003. Blair is still prime minister, but from now on he will have to justify his resolve to continue. He is the one on trial.